On Saturday (23May15), it was officially announced that Ireland had become the first country to legalise same-sex marriage by public vote, and Irish stars and outspoken supporters of Lesbian, Gay, Bisexual and Transgender (LGBT) rights took to social media to celebrate the historic moment and congratulate the 62 per cent of Irish citizens who voted 'yes'.

Openly-gay Smith wrote on Twitter.com, "Now can the rest of the world please follow in Ireland's footsteps? Please... So happy Ireland have passed the law to get married there. Still genuinely shocks me thou (though), that this is only just happening!!... Such a long way to go. But we can't give up until we are equal."

Fellow gay star MCKellen posted, "Congratulations to the Republic on saying yes to same-gender marriage! Now what about Northern Ireland?" and Lady GaGa wrote on Instagram.com, "Go to bed dreaming of the Supreme Court legalizing LGBT marriage in America, doze in gratitude that today it was legalized in Ireland. We are changing if slowly. And while actions are important, faith is too. Let's keep our faith that change is possible, and keep our courage."

Harris, who wed his partner David Burtka last year (14), wrote, "I proudly raise a pint glass of Guinness and toast the people of Ireland for voting by a sweeping majority to legalize same sex marriage!" while Miley Cyrus simply stated, "F**k yeah Ireland!" and Russell Crowe posted, "Dear Ireland, you are even more amazing."

Meanwhile, Irish actor Colin Farrell told E! Online, "Today Ireland has opened up her heart in a way that the whole world will feel... How we have changed our fortune in 24 hours, how we have lit the way, how we have guaranteed a brighter and more loving future for all who call this beautiful land home. Bravo citizens of Ireland."

Other celebrities celebrating the result online include British comedian Stephen Fry, U.S. chat show host Ellen DeGeneres, Ellen Page, Jessica Chastain, Alan Cumming, Modern Family star Jesse Tyler Ferguson and singer Josh Groban.